Mechanical calendar with automatic yearly cycle - has differential drive between shafts to allow for different lengths of months

摘要

A mechanically controlled calendar includes a facility for a completely automatic yearly cycle that takes account of variations in the length of months. The main drive is applied to the worm year input (1) to drive a main shaft (2) that cycles once per month. A chain drive of 1:1 (7, 8) and 11:12 (10, 11) connects the main shaft and an auxiliary (9). A cam (b, c) located on a drum (13) operates a lever to control the correcting rotation of the shaft to provide adjustment for the different lengths of the months.